Rodriguez 2007.

Methods	Design: randomised, double blind, parallel group study Duration: 2‐day run in, then 21‐day treatment period Setting: not stated
Participants	Persistent moderate or severe cancer pain (primarily gastric, breast, prostate, lung) N = 177 M 88, F 89 Mean age 60 years
Interventions	Codeine + paracetamol 150 mg + 2500 mg daily, n = 59 Hydrocodone + paracetamol 25 mg + 2500 mg daily, n = 62 Tramadol 200 mg daily, n = 56 If no PR (VAS ≥ 4/10) dose could be doubled. If this caused intolerable adverse events it could be reduced by 25% Rescue medication:
Outcomes	PI: 10 cm VAS PR: five‐point scale (0‐4) Adverse events Withdrawals
Notes	Oxford Quality Score: R = 2, DB = 2, W = 1. Total = 5/5
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"computer‐generated schedule"
Allocation concealment (selection bias)	Unclear risk	Method not described
Blinding of participants and personnel (performance bias) All outcomes	Low risk	"study drugs had similar characteristics such as color, shape, and dimensions and were packaged in identical containers"
Blinding of outcome assessment (detection bias) All outcomes	Low risk	"study drugs had similar characteristics such as color, shape, and dimensions and were packaged in identical containers"
Incomplete adverse event outcome data‐ patient level	Low risk	<90% participants included
Selective reporting bias for adverse events	Low risk	Comprehensive list
Size	Unclear risk	50 ‐ 199 participants per treatment arm